In the field of network communication and network administration, devices dispersed throughout one or more networks may provide connectivity across different networks and network segments (e.g., subnets, intranets, or the Internet). The practice of directing traffic across and through different portions of interconnected networks to that traffic's appropriate destination (e.g., device associated with correct destination address) is referred to as “routing.” The function of routing is normally performed by a network communication device called a “router.” As explained in more detail below, internal to a router is information maintained in routing tables that assist in directing traffic, in part, by transmitting that traffic through an appropriate network interface of the router so that it proceeds on its journey toward the appropriate destination address (and therefore device associated with that destination address). There are many routers that connect many different networks and subnets and each of them may perform an important function for the portions of the networks they serve. From a network administration perspective, maintenance of a vast number of unique routers may present a challenge.
In Internet Protocol (IP) based computer networks, virtual routing and forwarding (VRF) refers to a technology that allows multiple instances of a routing table to co-exist within the same network communication device (e.g., router) at the same time. In some cases, network functionality may be improved because network paths can be segmented without requiring multiple routers. A VRF may be implemented in a network device by distinct routing tables known as forwarding information bases (FIBs) that are discussed in more detail below. There is typically one FIB per routing instance. Alternatively, a network device may have the ability to configure different virtual routers, where each one has its own FIB that is not accessible to any other virtual router instance on the same network communication device.